纸张表面墨膜蒸发与渗透干燥的耦合建模

A coupled model of penetration and evaporation for ink film drying on plain paper

油墨干燥速率是影响印品质量的关键因素之一,干燥通常是油墨溶剂渗透和蒸发共同作用的结果。文中建立了考虑纸张和油墨内部导热、油墨内固体骨架等复杂因素的一维油墨干燥模型。渗透部分基于毛细管束模型,引入了蒸发对油墨黏度的影响;蒸发部分引入了油墨溶剂相分数的概念,分析了各界面处应满足的边界条件,实现了渗透和蒸发的耦合计算。模型揭示了孔隙率对蒸发速率的影响、对流换热系数对渗透速率的影响,能很好地再现实验数据。

Ink drying rate is one of the key factors influencing the quality of printing. Generally, the drying is carried out by simultaneous penetration and evaporation. A one-dimension drying model for ink film on plain paper was established, including the effects of the heat conduction in ink and paper and the solid components in ink. For penetration, the effect of evaporation on ink viscosity was introduced based on the bundles of capillary tubes. For evaporation, the fraction idea of the ink solvent phase was introduced, and the boundary conditions were analyzed, which should satisfy the coupled calculation of penetration and evaporation. The coupled model was used to study the influence of porosity on evaporation rate and that of heat transfer coefficient on penetration rate, and can recall the experimental data.